1. Field of the Invention
The present invention relates to method and apparatus of recording a multi-channel data stream on a recording medium, e.g., a writable high-density digital versatile disk (abbreviated to ‘HD-DVD’ hereinafter) in such a manner that substreams of digital channels constituting the multi-channel data stream can be distinguished from each other in reproduction.
The present invention further relates to a recording medium on which a multi-channel data stream is recorded in such a manner that sub streams of digital channels constituting the multi-channel data stream can be distinguished from each other in reproduction.
2. Description of the Related Art
Owing to technical improvement in the fields of video/audio data compression, digital modulation/demodulation, and so on, a digital television broadcast system broadcasting TV signals in the form of digital data streams is being standardized rapidly.
In the digital television broadcast system, audio/video (A/V) signals to be broadcast are compressed according to the data compressing rule specified by MPEG 2 (Moving Picture Experts Group) and the compressed A/V data are broadcasted in the form of a transport stream (TS), which is also defined in MPEG 2 standard, composed of successive 188-byte-long transport packets (TPs).
The digital TV broadcast system, which will be commercialized soon owing to technical improvement of A/V data compression and transmission, is able to support much higher-quality of video and audio than an analog TV system. Furthermore, it ensures data compatibility with a digital communication device, a digital storage device, etc.
In the meantime, a new device is being developed to prepare for commercialization of digital TV broadcast systems. That is a digital recorder being able to receive a TS of digital broadcast programs and to record the TS on a writable HD-DVD. Such a digital recorder will be widely used as digital TV broadcast systems are commercialized.
A single physical broadcast channel (called ‘RF channel’ in general) has about 6 MHz bandwidth which ensures 19.4 Mbps data rate. This data rate can carry a single HD-TV broadcast signal or about four SD-TV signals. Such a logical or virtual channel carrying one SD-TV signal in an RF channel is called ‘digital channel’.
In other words, a single RF channel sometimes includes several digital channels, namely, sub-channels which carry mutually-different broadcast programs.
Therefore, a DVD recorder being developed may have to record two or more digital channels simultaneously at a user's request. However, if a DVD recorder records a plurality of digital channels and creates management information through the same manner as it does for a single digital channel, a DVD could not tell digital channels apart among a recorded stream of digital channels. Namely, a user could not select only one program, i.e., one digital channel to be reproduced from among the plurality of recorded digital channels.